Examine source code of Arrow Cast

{
  "name": "Arrow Cast",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(0, 6, 18, 1)",
      "tab_background_text": "#bee8e2",
      "toolbar": "rgba(228, 233, 242, 0.1)",
      "toolbar_field": "rgba(0, 0, 0, 0)",
      "toolbar_field_text": "rgba(250, 250, 250, 1)"
    }
  }
}